Reordering Table View

I have a one column table view that gets it’s data from a 2 cell data source. Getting data in and out of the table view works great, but I cant get figure out how to allow drag n’ drop reordering. I tried following the example in applescript studio

set allows reordering of table view "tv_ac" of scroll view "sv_ac" of window "MainWindow" to true

But I get this error when the line tries to run “NSReceiverEvaluationScriptError: 4 (1)” Any ideas why this might be happening? I’m guessing it has to do with the datasource as the content of the tableview because I can’t find much else that seems different than the example.

Thanks.